It has already been proposed to use a carbodiimide compound as an end-capping agent for a polymer compound terminated with acidic groups, such as carboxyl groups, thereby inhibiting the hydrolysis of the polymer compound (Patent Document 1). The carbodiimide compound used in this proposal is a linear carbodiimide compound. When a linear carbodiimide compound is used as an end-capping agent for a polymer compound, upon the reaction that attaches the linear carbodiimide compound to the ends of the polymer compound, an isocyanate-group-containing compound is released. This results in the characteristic odor of an isocyanate compound, causing a problem in that the working environment is deteriorated.    [Patent Document 1] JP-A-2008-50584    [Patent Document 2] JP-A-2005-2174